While the invention is subject to a wide range of application, it is especially suitable for use in a security system interconnected by telephone circuits and will be particularly described in this connection.
There are a number of methods for providing security; including, guards, closed circuit television, and sonic devices. One particularly effective system is one that uses microphones to monitor sounds in an area with security personnel listening for unusual sounds indicating a dangerous situation. For example, a conventional intercommunication system can be operated with "live" microphones so that an individual monitoring the system can detect strange sounds indicating trespass or unauthorized activities. Such an arrangement may be a most effective system as a skilled individual can quickly evaluate a situation and determine if action is required. Unfortunately, such a system presents a most serious threat to the privacy of individuals located near the live microphones and therefore such a system is unacceptable to many people.